SAN FRANCISCO (KRON) — The California Department of Health has released new guidance for travelers coming from out-of-state, including residents who recently left California.

State health officials say those who are arriving in or returning to California from other states or countries should take a COVID-19 test once it’s been 3-5 days since arriving.

It’s not mandatory, but strongly suggested as COVID-19 cases have starting trending upwards again.

Officials also said people traveling from out-of-state should follow the CDC travel guidance and isolate if they test positive or start feeling COVID-19 symptoms.

The health department said the statewide seven-day average case rate has increased by 47% and hospitalizations have increased by 14% since Thanksgiving.

In addition, the recently-detected omicron variant of COVID-19 is likely more contagious than the original coronavirus, according to the CDC. “CDC expects that anyone with omicron infection can spread the virus to others, even if they are vaccinated or don’t have symptoms,” the agency said.

Officials do not yet know if omicron causes more severe illness than the original strain and other variants.

Besides the travel advisory, the state of California is also enforcing indoor mask-wearing in public spaces starting Wednesday.